Employee Benefit Plan - Plan Assets at Fair Value (Details) (USD $) In Thousands, unless otherwise specified										12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013 Level 1	Dec. 31, 2012 Level 1	Dec. 31, 2012 Level 2	Dec. 31, 2013 Level 3	Dec. 31, 2012 Level 3	Dec. 31, 2011 Level 3	Dec. 31, 2012 Fixed income investments	Dec. 31, 2012 Equity type investments	Dec. 31, 2013 Cash	Dec. 31, 2013 Cash Level 1	Dec. 31, 2012 Common/collective trusts	Dec. 31, 2012 Common/collective trusts U.S. short maturity fixed income investments	Dec. 31, 2012 Common/collective trusts U. S. Large Cap equities	Dec. 31, 2012 Common/collective trusts International equities	Dec. 31, 2012 Common/collective trusts Level 2	Dec. 31, 2012 Mutual funds	Dec. 31, 2012 Mutual funds Short term fixed income fund	Dec. 31, 2012 Mutual funds Level 2	Dec. 31, 2013 Money market funds	Dec. 31, 2012 Money market funds	Dec. 31, 2013 Money market funds Level 1	Dec. 31, 2012 Money market funds Level 1	Dec. 31, 2013 U.S. treasury securities	Dec. 31, 2013 U.S. treasury securities Level 1	Dec. 31, 2012 Other	Dec. 31, 2012 Other Level 3
Defined Benefit Plan Disclosure [Line Items]
Investment strategy range, minimum										65.00%	5.00%
Investment strategy range, maximum										95.00%	35.00%
Fair value of plan assets	$ 58,648	$ 60,097	$ 60,953	$ 58,648	$ 478	$ 58,692	$ 0	$ 927	$ 810			$ 115	$ 115	$ 34,936				$ 34,936	$ 23,756		$ 23,756	$ 697	$ 478	$ 697	$ 478	$ 57,836	$ 57,836	$ 927	$ 927
Percentage of fair value of investments															67.00%	25.00%	8.00%			100.00%